Discrepancies between your Campaign Summary information and your Billing Summary information for the same date range might occur for one or both of the reasons below:

Time Reporting Differences
All data in the Account Performance Reports (including the Campaign Summary report) will be displayed in the time zone in which the account is based. However, Billing Reports will be generated in the Pacific time zone, which may lead to some discrepancies between your Performance and Billing Reports. In addition, billing transactions (including credit card transactions) can sometimes be recorded out of chronological order.

Service Adjustments
From time to time, you might receive adjustments that count as credits toward your account. This means that you're billed less than what's shown on your Campaign Summary.